The present invention relates to micro-surgical or non-surgical scissors, which have superimposed blades that are flexible and may be complementary curved. The invention additionally relates to forceps that can be used in microsurgery or other fields in which precise gripping of objects is required. The handle portions of the forceps that control the movement of the blades are resilient bands, or spring arms, so that a minimum of force is required to reliably operate the blades of the forceps and also to apply a pressure release mechanism where excess pressure is released due to the flexibility of the material being used.
U.S. Pat. No. 4,527,331 to Lasner et al. shows a suture removing and continuous band scissors having twisted and crossover shanks that are provided with both a cutting and shear blade. That patent is incorporated herein by reference. However, the concept of the above patent is advanced by using sharpened cutting blades that form an arc across one another beyond the optimum shearing angle of heat treated scissors and which results in the scissors always cutting at the points of the blades. The scissors have an intermediate handle portion and rear interconnected metal bands or spring arms, which results in stress relief for the instrument. Furthermore, in accordance with the present invention, the cutting instrument, having rear spring arms that can be operated with a minimum of finger pressure, results a reduction in finger and hand fatigue of the surgeon or other user, while at the same time providing a film holding action.
An alternate embodiment of the invention discloses a continuous band scissors, which is a closed system for increasing energy in the system. The alternate embodiment of the present scissors invention has the advantage of being a closed system whereby energy is trapped within the system and upon continual squeezing goes back to the fulcrum and provides for stronger cutting action of the preferably curved blades.
The prior art forceps that are fabricated of heat-treated metal tend to meet only at the tip. Therefore, when the tips come together and are further pressed resistance is created which will cause the spring to flex and flatten out. In the present invention, on the other hand, the platforms meet initially over the entire surface and are maintained over the entire surface because of the use of spring steel instead of heat treated steel. Furthermore, in the present invention forceps can be reshaped after continual use in order to achieve complete mating of the platforms or in the alternative, the angles of the shanks can be increased or decreased manually resulting in the at rest jaw opening to assume a desired opening or closing distance. This procedure cannot be carried out with heat-treated steel because of the possibility of fracture.
In the present invention the double twist of the forceps is structured with a pivot in-between the two spaced twists, and is also the three point mechanical fixation for optimum stability of operation. Furthermore, the forceps cannot be oversqueezed since the pressure built up in the forceps is relieved out of the back, which is slidingly interconnected. This arrangement is especially valuable with regard to surgery when handling tissue, and can also be used in any field where delicacy of force is required, such as jewelry fabrication.
It is also within the concept of the present forceps invention to place carbon inserts into the platforms or blades so the forceps can be used as a surgical needle holder or to remove metal filings that cannot be successfully gripped by ordinary forceps. The forceps can be used in dentistry, for example, for use with matrix retainers, crown holders as well as with tissue. In addition, the use of carbide inserts in forceps may be successfully utilized as a root canal silver point extraction device for use by endodontists.
It is a feature of the present invention to provide scissors for micro-surgical or general use having sharpened curved blades and in which the handle portion and rear interconnected spring arms are of different Rockwell C hardness so the instrument required less finger pressure for operation, resulting in reduced finger and hand fatigue for the surgeon.
It is another object of the present invention to provide a scissors of non-heatable steel having sharpened curved or flat blades of resiliently flexible material which form an arc across one another and whereby energy is trapped in a closed system and upon continual squeezing returns to the fulcrum thus providing a stronger cutting action for the blades, thus permitting the tips of the blades to cut thicker material.
It is a feature of the present invention to provide flat interengaging forceps blades, intermediate handle portions for the blades, and spring steel arms which are separate components at the end remote from the forceps blades and which can be assembled and attached to the free ends of the intermediate handle portions to provide a surgical forceps for surgical or other precise usage, which is relatively easy and inexpensive to assemble.
It is another feature of the present invention to provide a part attached to the handle for the forceps constituting a pair of removably interconnected spring bands, preferably of stainless steel, and which are of such a gauge as to be easily and readily pressed toward each other, thus reducing finger and hand fatigue.
A further object of the present invention is to provide forceps having twists of substantially 90xc2x0 in front of and behind the pivot for the blades whereby the shanks of the forceps can be manually manipulated toward and away from each other to adjust the opening or closing of the blades at rest.